1. Field of the Invention
The invention pertains to the field of an apparatus for powering a human-powered machine. More particularly, the invention pertains to a linear driving mechanism suitable for a bicycle.
2. Description of the Related Art
Conventional bicycles are mostly driven by circular motion of crank pedals. However, only a small portion of the 360.degree. rotation of the crank is used to propel the bicycle; the rest is rotary motion and is wasted. Rotary crank pedals do not provide a uniform effective conversion of the substantially linear driving force exerted by a rider into drive torque. Thus, a rider expends excessive energy and fatigues more quickly. Since the pedal stroke of circular crank pedals cannot be adjusted, and a full turn of the crank pedal is inevitably required to drive the conventional bicycle, the rider's legs and stroke pattern do not always fit with the crank's pedal circular motion stroke.
Although lever propelled bicycles, propelled by up and down arcuate motion levers have been proposed, the mechanisms used for transmitting the motion of energy of the levers to a drive wheel has not been satisfactory. Since a majority of these solutions do not provide a true linear drive mechanism, they do not provide a 100% efficiency in the stroke. Furthermore, these solutions have failed to provide a mechanism by which an individual can power a vehicle on a backward and forward stroke.
Therefore, bicyclists and bicycle manufacturers are in need of a linear drive system which provides true linear driving capabilities as well as the capability to drive the bicycle upon an upward and backward stroke of the pedals.